1. Field of the Invention
The present invention relates to a device, used in an apparatus for alternately unrolling and supplying strip-like materials, e.g., strip-like wrapping papers for wrapping cigarettes from at least two rolls without interrupting supply of the strip-like materials, for, when a strip-like material unrolled and supplied from one roll is used up, joining the leading end of a new strip-like material unrolled from the other roll to the trailing end of the supplied strip-like material.
2. Description of the Related Art
As a conventional device of this type, a joining device disclosed in Published Unexamined Japanese Patent Application No. 63-162434 is known. This joining device overlays a leading end portion of a new wrapping material unrolled from the other roll on a trailing end portion of a strip-like wrapping material unrolled and supplied from one roll, and joins the trailing and leading end portions of these wrapping materials by a joining tape. However, in the conventional joining device, since the trailing and leading end portions of the wrapping materials are joined while they overlap each other, the overlapping portion may cause troubles in the following wrapping process or the like. In this joining device, a joining tape must be supplied to both the trailing end portion of the already supplied wrapping material, and the leading end portion of a new wrapping material, resulting in a complicated supply mechanism of a joining tape. The complicated mechanism also impairs reliability of an operation.